lamboot - Start a LAM multicomputer.


SYNTAX

       lamboot [-bdhvxH] [<bhost>]


OPTIONS

       -b      Assume  local and remote shell are the same.  This
               means that only one  remote  shell  invocation  is
               used  to each node.  If -b is not used, two remote
               shell invocations are used to each node.

       -d      Turn on debugging output.  This implies -v.

       -h      Print the command help menu.

       -s      Close stdio on the local node.

       -v      Be verbose.

       -x      Run in fault tolerant mode.

       -H      Do not display the command header.


DESCRIPTION

       The lamboot tool starts the LAM software on  each  of  the
       machines  specified in the boot schema, <bhost>.  The boot
       schema specifies the hostnames of nodes to be used in  the
       run-time  MPI  environment,  and  optionally lists how may
       CPUs LAM may used on each node.   The  user  may  wish  to
       first  run  the  recon(1)  tool  to verify that LAM can be
       started.

       Starting LAM is a three  step  procedure.   In  the  first
       step,  hboot(1)  is  invoked  on  each  of  the  specified
       machines.  Then each machine allocates a dynamic port  and
       communicates  it  back to lamboot which collects them.  In
       the third step, lamboot gives each  machine  the  list  of
       machines/ports  in  order to form a fully connected topol­
       ogy.  If any machine was not able to start, or if a  time­
       out  period  expires before the first step completes, lam­
       boot invokes wipe(1) to  terminate  LAM  and  reports  the
       error.

       The  <bhost> file is a LAM boot schema written in the host
       file syntax.  See bhost(5).  Instead of the command  line,
       a boot schema can be specified in the LAMBHOST environment
       variable.  Otherwise a default file, bhost.def,  is  used.
       LAM  searches for <bhost> first in the local directory and
       then in the installation directory under etc/.

       In addition, lamboot uses a process schema for  the  indi­
       vidual  LAM  nodes.   A  process schema (see conf(5)) is a
       description  of  the  processes   which   constitute   the

       istrator maintains this file -- LAM/MPI users will  gener­
       ally  not  need  to change this file.  It is also possible
       for the user to customize the LAM software with a  private
       process schema.

   Remote shell invocation
       The  remote  shell program that is used to invoke commands
       on remote hosts is set when LAM is configured.  It is typ­
       ically  rsh, but can be set to any value by the person who
       setup/compiled LAM.  This program  can  be  overridden  at
       lamboot  invocation time by setting the LAMRSH environment
       variable to a suitable remote shell program.  For example:

              setenv LAMRSH "ssh -x"

       This will force LAM to use the "ssh" client to invoke pro­
       grams on remote nodes, and ensure that "ssh" uses  the  -x
       command  line  flag (to suppress the ssh 1.x client series
       standard information banner that is normally output to the
       standard error, which would cause lamboot to fail).

       Normally,  lamboot  uses  two  remote shell invocations to
       each node.  The first remote shell invocation is  used  to
       determine the user's shell on the remote node.  The second
       remote shell invocation is used to launch the desired  LAM
       binary on the remote node.  If the -b switch is used, lam­
       boot will assume that the user's shell on all remote nodes
       is the same as it is on the local node, and therefore only
       one remote shell invocation is used,  which  is  noticably
       faster.

       In  either  case,  on remote nodes, if the user's shell is
       not csh, tcsh, or bash, .profile is invoked by LAM  before
       invoking  any  LAM  binary.  This allows the user to setup
       paths and any necessary environment  before  LAM  binaries
       are  invoked  (csh  and  tcsh  users can put such setup in
       their $HOME/.cshrc or $HOME/.tcshrc files; bash users  can
       put this setup in their $HOME/.bashrc file).

   Closing stdio
       The  stdio  of  each  LAM  daemon on a remote host that is
       launched by lamboot is closed by default.   Normally,  the
       stdio of the LAM daemon launched on the local host is left
       open so that the  internal  LAM  tstdio(3)  package  works
       properly.  However, it is sometimes desirable to close the
       stdio of the local LAM daemon as well.  For example:

          rsh somenode lamboot -s hostfile

       This is because rsh waits for two conditions before  exit­
       ing:  lamboot  to  exit, and stdout / stderr to be closed.
       Without -s, stdout / stderr would not be closed,  and  rsh
       would  hang  even though lamboot had completed.  -s causes

       upon  invocation, which will allow rsh to complete.  Using
       -s will not affect lamboot in any other way, but  it  will
       prevent the tstdio(3) package from working properly.

   Fault Tolerance
       If  the  -x  option  is  given, LAM runs in fault tolerant
       mode.  In this mode, nodes exchange  ``heart  beat''  mes­
       sages  periodically to make sure all nodes are running and
       the links connecting them are operational.  When a  node's
       heart  beats  stop,  it  is  declared ``dead'' and all LAM
       nodes (and processes) are notified.  This allows users  to
       write  fault tolerant applications that can degrade grace­
       fully, or fully recover by replacing the defunct node with
       another  (see  lamgrow(1)).   Since this mode introduces a
       performance penalty, it is not activated by default.


EXAMPLES

       lamboot -v
           Start LAM on the machines  described  in  the  default
           boot schema.  Report about important steps as they are
           done.

       lamboot mynodes
           Start LAM on the machines described in the boot schema
           mynodes.  Operate silently.


FILES

       $LAMHOME/etc/lam-bhost.def default boot schema file

       $LAMHOME/etc/lam-conf.lam  default  process  schema  file
                                         for LAM nodes


SEE ALSO

       recon(1), wipe(1), hboot(1), tstdio(3), bhost(5), conf(5),
       lam-helpfile(5)


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